/* GDK - The GIMP Drawing Kit
* Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see <http://www.gnu.org/licenses/>.
*/
/*
* Modified by the GTK+ Team and others 1997-2000. See the AUTHORS
* file for a list of people on the GTK+ Team. See the ChangeLog
* files for a list of changes. These files are distributed with
* GTK+ at ftp://ftp.gtk.org/pub/gtk/.
*/
#include "config.h"
#include "gdkrgba.h"
#include <string.h>
#include <errno.h>
#include <math.h>
#include "fallback-c89.c"
/**
* SECTION:rgba_colors
* @Short_description: RGBA colors
* @Title: RGBA Colors
*
* #GdkRGBA is a convenient way to pass rgba colors around.
* It’s based on cairo’s way to deal with colors and mirrors its behavior.
* All values are in the range from 0.0 to 1.0 inclusive. So the color
* (0.0, 0.0, 0.0, 0.0) represents transparent black and
* (1.0, 1.0, 1.0, 1.0) is opaque white. Other values will be clamped
* to this range when drawing.
*/
G_DEFINE_BOXED_TYPE (GdkRGBA, gdk_rgba,
gdk_rgba_copy, gdk_rgba_free)
/**
* GdkRGBA:
* @red: The intensity of the red channel from 0.0 to 1.0 inclusive
* @green: The intensity of the green channel from 0.0 to 1.0 inclusive
* @blue: The intensity of the blue channel from 0.0 to 1.0 inclusive
* @alpha: The opacity of the color from 0.0 for completely translucent to
* 1.0 for opaque
*
* A #GdkRGBA is used to represent a (possibly translucent)
* color, in a way that is compatible with cairo’s notion of color.
*/
/**
* gdk_rgba_copy:
* @rgba: a #GdkRGBA
*
* Makes a copy of a #GdkRGBA.
*
* The result must be freed through gdk_rgba_free().
*
* Returns: A newly allocated #GdkRGBA, with the same contents as @rgba
*
* Since: 3.0
*/
GdkRGBA *
gdk_rgba_copy (const GdkRGBA *rgba)
{
return g_slice_dup (GdkRGBA, rgba);
}
/**
* gdk_rgba_free:
* @rgba: a #GdkRGBA
*
* Frees a #GdkRGBA created with gdk_rgba_copy()
*
* Since: 3.0
*/
void
gdk_rgba_free (GdkRGBA *rgba)
{
g_slice_free (GdkRGBA, rgba);
}
#define SKIP_WHITESPACES(s) while (*(s) == ' ') (s)++;
/* Parses a single color component from a rgb() or rgba() specification
* according to CSS3 rules. Compared to exact CSS3 parsing we are liberal
* in what we accept as follows:
*
* - For non-percentage values, we accept floats in the range 0-255
* not just [0-9]+ integers
* - For percentage values we accept any float, not just
* [ 0-9]+ | [0-9]* “.” [0-9]+
* - We accept mixed percentages and non-percentages in a single
* rgb() or rgba() specification.
*/
static gboolean
parse_rgb_value (const gchar *str,
gchar **endp,
gdouble *number)
{
const char *p;
*number = g_ascii_strtod (str, endp);
if (errno == ERANGE || *endp == str ||
isinf (*number) || isnan (*number))
return FALSE;
p = *endp;
SKIP_WHITESPACES (p);
if (*p == '%')
{
*endp = (char *)(p + 1);
*number = CLAMP(*number / 100., 0., 1.);
}
else
{
*number = CLAMP(*number / 255., 0., 1.);
}
return TRUE;
}
/**
* gdk_rgba_parse:
* @rgba: the #GdkRGBA to fill in
* @spec: the string specifying the color
*
* Parses a textual representation of a color, filling in
* the @red, @green, @blue and @alpha fields of the @rgba #GdkRGBA.
*
* The string can be either one of:
* - A standard name (Taken from the X11 rgb.txt file).
* - A hexadecimal value in the form “\#rgb”, “\#rrggbb”,
* “\#rrrgggbbb” or ”\#rrrrggggbbbb”
* - A RGB color in the form “rgb(r,g,b)” (In this case the color will
* have full opacity)
* - A RGBA color in the form “rgba(r,g,b,a)”
*
* Where “r”, “g”, “b” and “a” are respectively the red, green, blue and
* alpha color values. In the last two cases, r g and b are either integers
* in the range 0 to 255 or percentage values in the range 0% to 100%, and
* a is a floating point value in the range 0 to 1.
*
* Returns: %TRUE if the parsing succeeded
*
* Since: 3.0
*/
gboolean
gdk_rgba_parse (GdkRGBA *rgba,
const gchar *spec)
{
gboolean has_alpha;
gdouble r, g, b, a;
gchar *str = (gchar *) spec;
gchar *p;
g_return_val_if_fail (spec != NULL, FALSE);
if (strncmp (str, "rgba", 4) == 0)
{
has_alpha = TRUE;
str += 4;
}
else if (strncmp (str, "rgb", 3) == 0)
{
has_alpha = FALSE;
a = 1;
str += 3;
}
else
{
PangoColor pango_color;
/* Resort on PangoColor for rgb.txt color
* map and '#' prefixed colors
*/
if (pango_color_parse (&pango_color, str))
{
if (rgba)
{
rgba->red = pango_color.red / 65535.;
rgba->green = pango_color.green / 65535.;
rgba->blue = pango_color.blue / 65535.;
rgba->alpha = 1;
}
return TRUE;
}
else
return FALSE;
}
SKIP_WHITESPACES (str);
if (*str != '(')
return FALSE;
str++;
/* Parse red */
SKIP_WHITESPACES (str);
if (!parse_rgb_value (str, &str, &r))
return FALSE;
SKIP_WHITESPACES (str);
if (*str != ',')
return FALSE;
str++;
/* Parse green */
SKIP_WHITESPACES (str);
if (!parse_rgb_value (str, &str, &g))
return FALSE;
SKIP_WHITESPACES (str);
if (*str != ',')
return FALSE;
str++;
/* Parse blue */
SKIP_WHITESPACES (str);
if (!parse_rgb_value (str, &str, &b))
return FALSE;
SKIP_WHITESPACES (str);
if (has_alpha)
{
if (*str != ',')
return FALSE;
str++;
SKIP_WHITESPACES (str);
a = g_ascii_strtod (str, &p);
if (errno == ERANGE || p == str ||
isinf (a) || isnan (a))
return FALSE;
str = p;
SKIP_WHITESPACES (str);
}
if (*str != ')')
return FALSE;
str++;
SKIP_WHITESPACES (str);
if (*str != '\0')
return FALSE;
if (rgba)
{
rgba->red = CLAMP (r, 0, 1);
rgba->green = CLAMP (g, 0, 1);
rgba->blue = CLAMP (b, 0, 1);
rgba->alpha = CLAMP (a, 0, 1);
}
return TRUE;
}
#undef SKIP_WHITESPACES
/**
* gdk_rgba_hash:
* @p: (type GdkRGBA): a #GdkRGBA pointer
*
* A hash function suitable for using for a hash
* table that stores #GdkRGBAs.
*
* Returns: The hash value for @p
*
* Since: 3.0
*/
guint
gdk_rgba_hash (gconstpointer p)
{
const GdkRGBA *rgba = p;
return ((guint) (rgba->red * 65535) +
((guint) (rgba->green * 65535) << 11) +
((guint) (rgba->blue * 65535) << 22) +
((guint) (rgba->alpha * 65535) >> 6));
}
/**
* gdk_rgba_equal:
* @p1: (type GdkRGBA): a #GdkRGBA pointer
* @p2: (type GdkRGBA): another #GdkRGBA pointer
*
* Compares two RGBA colors.
*
* Returns: %TRUE if the two colors compare equal
*
* Since: 3.0
*/
gboolean
gdk_rgba_equal (gconstpointer p1,
gconstpointer p2)
{
const GdkRGBA *rgba1, *rgba2;
rgba1 = p1;
rgba2 = p2;
if (rgba1->red == rgba2->red &&
rgba1->green == rgba2->green &&
rgba1->blue == rgba2->blue &&
rgba1->alpha == rgba2->alpha)
return TRUE;
return FALSE;
}
/**
* gdk_rgba_to_string:
* @rgba: a #GdkRGBA
*
* Returns a textual specification of @rgba in the form
* `rgb (r, g, b)` or
* `rgba (r, g, b, a)`,
* where “r”, “g”, “b” and “a” represent the red, green,
* blue and alpha values respectively. r, g, and b are
* represented as integers in the range 0 to 255, and a
* is represented as floating point value in the range 0 to 1.
*
* These string forms are string forms those supported by
* the CSS3 colors module, and can be parsed by gdk_rgba_parse().
*
* Note that this string representation may lose some
* precision, since r, g and b are represented as 8-bit
* integers. If this is a concern, you should use a
* different representation.
*
* Returns: A newly allocated text string
*
* Since: 3.0
*/
gchar *
gdk_rgba_to_string (const GdkRGBA *rgba)
{
if (rgba->alpha > 0.999)
{
return g_strdup_printf ("rgb(%d,%d,%d)",
(int)(0.5 + CLAMP (rgba->red, 0., 1.) * 255.),
(int)(0.5 + CLAMP (rgba->green, 0., 1.) * 255.),
(int)(0.5 + CLAMP (rgba->blue, 0., 1.) * 255.));
}
else
{
gchar alpha[G_ASCII_DTOSTR_BUF_SIZE];
g_ascii_formatd (alpha, G_ASCII_DTOSTR_BUF_SIZE, "%g", CLAMP (rgba->alpha, 0, 1));
return g_strdup_printf ("rgba(%d,%d,%d,%s)",
(int)(0.5 + CLAMP (rgba->red, 0., 1.) * 255.),
(int)(0.5 + CLAMP (rgba->green, 0., 1.) * 255.),
(int)(0.5 + CLAMP (rgba->blue, 0., 1.) * 255.),
alpha);
}
}